Wood County reporter. [volume] (Grand Rapids [i.e. Wisconsin Rapids], Wis.) 1857-1923, 1887-10-20

When the evening was sufficiently
advanced the great Pulkova glass was
placed in its temporary fitting in the
garden. There was no moon and the
darkness was intense. The glass was
brought on a four-wheel hand truck
and lifted into the tube by five men
and fixed by revolving it III the screw
fitting. The tube was forty-fye feet
long and weighed with the attending
fittings about seven tons. Two piles
of briekwork supported the whole.
There was no clockWork movement
and the toughest apparatus was en-
ployed, the telescope was raised and
moved by guide-rope, the motion of
ali equatorial movement being imitat-
ed by using common Windlass. AS
the motion of the earth caused the OBJ
iect to pass across the field of the tele-
scope, the observer gave the order,
'Follow," when slight turn of the
windlass kept the object in view. Such
were the rough appliances used to test
this 100000 lens.
The planets had all set, and / had to
be satisfied with view of fixed star,
which is an excellent object for test
ing the optical properties of lens,
but very uninteresting otherwise, as the
largest telescope can make little inn
preston on a fixed star; no disc can be
seen, merely speck of light. The
star selected was a small one, and
barely visible as pale minute object.
On looking at it with this magnificent
instrument its wonderful light-gather-
ing powers were at once evident, for
the star shone with the luster and
brilliancy of an electric light. It
was an object which brought out all
the imperfections OF the glass, and to
the eyes of Mr.. Clark and his sons
many were evident, and, it was said,
two months work was necessary tG
correct them. During the trial the
lens was lowered and five men re-
volyed the glass in its fitting. On its
being placed in position again one OF
the sons was about to make another
test, when the old man shouted.
ait, boys, let her COOL"
| was curious to know what this
could mean, and Alvan Clark explained
that the correction was so delicate
that the heat from the hands of the
five men holding the metal case of
the objective would change the cor
rection, SO it had to sscool"
On the front or crown glass lens was
very marked flaw, due to the lap
ping over of stratum of glass in
cooling. By measurement [ found it
to be one and quarter inches long,
by one-eighth of an inch in diameter,
almost IN the center of the lens, near
the front surface. This was very
provoking circumstance in a $50, 900
glass. Mr.. Clark had ordered another
disc of glass, but Professor Won Otto
Streuye decided to accept the damaged
one, at least for time, as it seemed
very doubtful when another glass
might be expected to be made in
France. This flaw would not alter the
definition of the lens, but would stop
fractional parts of lightpassine through
the lens.
In conversation with Mr.. Clark on
the advantages of immense telescopes
such as this one, he admitted that the
telescopes of moderate aperture, say
from ten to fifteen inches, were prefer
able for general use even for the high
est purposes. He spoke with pride Of
such an instrument he had made, with
which he had seen all that could be
seen even with colossal telescopes.
Only one discovery has been made
with the WASHINGTON telescope OF